【HarmonyOS】【JAVA UI】HarmonyOS 网络HttpURLConnection的基本使用

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 参考资料

权限开发指导

线程管理

在鸿蒙（HarmonyOS）环境下，优雅的完成Http访问网络【教程】

api讲解

创建 url

URL url=new URL(urlstr);//todo 创建 url

得到HttpURLConnection对象

HttpURLConnection httpURLConnection= (HttpURLConnection) url.openConnection();

设置请求方式

httpURLConnection.setRequestMethod(“GET”);

建立连接

httpURLConnection.connect()

得到请求状态码

int code=httpURLConnection.getResponseCode()

代码如下

        try {
            String urlstr="https://www.baidu.com/";
            URL url=new URL(urlstr);//todo  创建 url
            //todo 得到HttpURLConnection对象
            HttpURLConnection httpURLConnection= (HttpURLConnection) url.openConnection();
            httpURLConnection.setRequestMethod("GET");//todo 设置请求方式
            httpURLConnection.connect();//todo 建立连接
            int code=httpURLConnection.getResponseCode();//todo 获取请求状态码
            if(code==HttpURLConnection.HTTP_OK){
              //todo  请求成功 处理相关业务
            }else{
            //todo 失败业务处理
            }


        }catch (Exception e){
            e.printStackTrace();
        }

代码运行

config.json添加权限

  "reqPermissions": [{"name":"ohos.permission.INTERNET"}],

设置访问模式

  "deviceConfig": {
    "default": {
      "network": {
        "cleartextTraffic": true
      }
    }
  },

xml布局绘制（在xml 布局设置两个text按钮，一个用text于点击发起网络请求，一个text用于显示网络请求得到的结果）代码和效果如下

<?xml version="1.0" encoding="utf-8"?>
<DirectionalLayout
    xmlns:ohos="http://schemas.huawei.com/res/ohos"
    ohos:height="match_parent"
    ohos:width="match_parent"
    ohos:orientation="vertical">

    <Text
        ohos:id="$+id:text_helloworld"
        ohos:height="match_content"
        ohos:width="match_parent"
        ohos:text_alignment="center"
        ohos:background_element="#ed6162"
        ohos:layout_alignment="horizontal_center"
        ohos:text="网络请求"
        ohos:text_size="40vp"
        />

    <Text
        ohos:id="$+id:TextResult"
        ohos:height="match_parent"
        ohos:width="match_parent"
        ohos:text_alignment="top|left"
        ohos:text="结果"
        ohos:multiple_lines="true"
        ohos:text_size="20vp"
        />

</DirectionalLayout>

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java代码实现（分为三个方法 第一个方法实现点击事件 ，第二个方法实现网络请求的事件，第三个方法输入流转化为字符串的功能，最后子线程切换到ui主线程，显示字符串）代码如下

package com.harmony.alliance.myapplication.slice;

import com.harmony.alliance.myapplication.ResourceTable;
import ohos.aafwk.ability.AbilitySlice;
import ohos.aafwk.content.Intent;
import ohos.agp.components.Component;
import ohos.agp.components.Text;
import ohos.hiviewdfx.HiLog;
import ohos.hiviewdfx.HiLogLabel;

import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

public class MainAbilitySlice extends AbilitySlice {
    static final HiLogLabel LABEL = new HiLogLabel(HiLog.LOG_APP, 0x00201, "MY_TAG");
 Text textResult;
    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        super.setUIContent(ResourceTable.Layout_ability_main);
        //todo 用于显示结果的按钮
        textResult=findComponentById(ResourceTable.Id_TextResult);
        //todo 实现点击事件
        findComponentById(ResourceTable.Id_text_helloworld).setClickedListener(new Component.ClickedListener() {
            @Override
            public void onClick(Component component) {
                //todo 开启线程
                new Thread(){
                    @Override
                    public void run() {
                        super.run();
                        networkGet();
                    }
                }.start();

            }
        });
    }

    /**
     * 发起网络请求
     */
    public  void  networkGet(){
        try {
            String urlstr="https://www.baidu.com/";
            URL url=new URL(urlstr);//todo  创建 url
            //todo 得到HttpURLConnection对象
            HttpURLConnection httpURLConnection= (HttpURLConnection) url.openConnection();
            httpURLConnection.setRequestMethod("GET");//todo 设置请求方式
            httpURLConnection.connect();//todo 建立连接
            int code=httpURLConnection.getResponseCode();//todo 获取请求状态码
            if(code==HttpURLConnection.HTTP_OK){
                InputStream inputStream=httpURLConnection.getInputStream();//todo 获取网络得到输入流
                byte[] data = read(inputStream);//todo 转化为字节
                String html = new String(data, "UTF-8");// todo 字节转化为字符串
                HiLog.error(LABEL,html);
                //todo 从子线程切换到Ui 主线程
                getUITaskDispatcher().syncDispatch(()   -> {
                    textResult.setText(html);//todo 显示结果
                });
            }


        }catch (Exception e){
            e.printStackTrace();
        }
    }

    /**
     * 输入流转化为字节
     * @param inStream 输入流
     * @return 返回字节
     * @throws Exception 抛出的异常
     */
    public static byte[] read(InputStream inStream) throws Exception{
        ByteArrayOutputStream outStream = new ByteArrayOutputStream();
        byte[] buffer = new byte[1024];
        int len = 0;
        while((len = inStream.read(buffer)) != -1)
        {
            outStream.write(buffer,0,len);
        }
        inStream.close();
        return outStream.toByteArray();
    }

}

运行效果

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